Improvement in watch-case springs



lw'. FENlMonE. Improvement in Watch-Case Springs.

Patented May 3.0;1871.A

Mal/1655.65

PATENT OFFICE.

WESLEY FENIMORE, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN WATCH-CASE SPRINGS.

Specification forming part of Letters Patent No. 115,455, dated May 30, 1871.

I, WESLEY FENIMORE, of Philadelphia, county of Philadelphia, State oi' Pennsylvania, have invented an Improved Watch-Gasc Spring, of which the following is a specitication:

Nature and Object of the Inccntion.

My invention consists of awatch-case spring, constructed in the peculiar manner too fully explained hereafter to need preliminary eX- planation, with the View of preventing fracture, which frequently occurs in watch-case springs constructed in the usual manner.

Description of the Accompanying Drawing.

Figure 1 is a sectional plan of part ot' a watch-case with an ordinary spring; and Figs. 2, and it illustrate different modes of constructing my improved spring.

General Description.

In Fig. l, which illustrates the ordinary Watch-case spring, A represents a sectional plan of part of the central ring of the case, this ring being recessed or chambered on the inside, as usual. The ordinary spring B consists of a segmental block of steel, bent to suit the annular chamber a, and reduced in thickness from x to y, which is the only portion possessing elasticity, the remaining portion being solid and rigid, and iittin g snugly in the chamber a, where it is secured by a small screw, m.

In making the usual spring it is the practice to iirst procure a segmental piece of steel of uniform thickness adapted to the chamber c, and then to reduce so much of the piece in thickness as may be required to possess elasticity and assume the character of a spring. This reduction must, of course, be made while the steel is soft, and the part reduced must be made elastic by hardening and tempering. It is a difficult matter to impart to these springs an even temper throughout; hence they are apt to break, especially at'the point I overcome this objection by making the elastic portion and the rigid portion, which has to tit in the annular chamber, separate. Thus, in Fig. 2, B is a rigid segmental block, shaped to lit snugly in the chamber a; and D is a strip ot' steel, tted into a slot in one end ofthe block'and secured thereto. rPhe spring D is part of a strip ot spring-steel, having the proper temper imparted to it, so that it has the desired elastic property bei'ore it is secured to the block; and hence the spring possesses the well-known superior quality due to an uudisturbed skin, which, by the old plan, is re moved in reducing the block.

Instead of securing the spring to a solid block, as described, the rigid portion adapted to the chamber may be composed of two plates, secured one to each side ot' the spring, as shown in Fig. 3; or the spring may be screwed into a solid segmental block, as shown in Fig. 4, the same object being attained in all casesnamely, a tough, properly-tempered spring, with undisturbed skin, attached to a rigid block.

It will be understood that the outer end of the spring is bent and shaped in the usual manner, so as to form a clasp for the back or front of the watchcase.

Claim.

A watch-case spring, consisting of a block adapted to but detachable from the case of a Watch, and a strip of steel having an uncut skin formed in drawing or rolling the said strip and secured to said block, as speciiied.

In testimony whereof I have signed myname to this specification in the presence of two subscribing witnesses.

WESLEY FENIMORE.

Witnesses WM. A. STEEL, FRANK. B. RICHARDS. 

